Process of contacting hydrocarbon vapors with zinc chloride



Patented Aug. 29, 1939 PATENT OFFICE PROCESS OF CONTACTING HYDROCARBONVAPORS WITH ZINC CHLORIDE Franklin E. Kimball, Los Angeles, Calif.

No Drawing. Application May 14, 1938, Serial No. 207,956

3 Claims.

This invention is a continuation-in-part of my co-pending applicationSerial No. 133,262 filed March 26, 1937 for a similar process ofrefining mineral oil with NH4Zn2Cl5 which has been issued 5 as UnitedStates Patent No. 2,121,169 on June 21,

This invention relates to the process of contacting hydrocarbon vaporswith zinc chloride in the liquid phase. It has for its object to renderthe process more expeditious and considerably cheaper.

The prevention of the separation of the solid phase of the zinc chloridehas hitherto been effected by the sufficiency of the water necessary todissolve the zinc chloride. This presence of the sufliciency of thewater necessary to dissolve the zinc chloride has hitherto been effectedby the sufiiciency of the steam necessary to maintain the equilibriumbetween the concentration of the water present and the concentration ofthe steam present. The volume of the hydrocarbon vapors which havehitherto been contacted with the zinc chloride in the liquid phase hashitherto been constricted by this presence of the sufficiency of thesteam necessary to maintain the equilibrium between the concentration ofthe water present and the concentration of the steam present.

Now, instead of incurring this steam constriction of the volume of thehydrocarbon vapors which are contacted with the zinc chloride in theliquid phase, I employ the use of the sufiiciency of the ammoniumpentachlorodizincate necessary to prevent the separation of the solidphase of the zinc chloride at the temperature below themelting-temperature of zinc chlorideand at the temperature above thefusion-temperature of the fused mixture of the ammoniumpentachlOrodizincate and of the zinc chloride.

The hereinabove used term, namely ammonium pentachlorodizincate, ishereby stipulated to be herein interpreted as being the name of thechemical compound whose chemical composition the scientific means ofchemical analysis shows to be 5 conforming to the chemical compositionwhich is represented by the chemical formula NI-I4Zn2Cl5.

Now, for the most part, this employed fused mixture of ammoniumpentachlorodizincate and zinc chloride was found to be an eutecticmixture 50 of ammonium pentachlorodizincate and zinc chloride whichfluxed at a temperature below 450 degrees Fahrenheit. It was also foundthat it could be prepared by the means of the employment of the use ofammonium chloride. A first 55 mixture of approximately one part ofammonium chloride and seven parts of zinc chloride was prepared whichfiuxed at a temperature of approximately 450 degrees Fahrenheit. Also, asecond mixture of approximately equi-molecular parts of ammoniumpentachlorodizincate and 5 zinc chloride was prepared which. fluxed at atemperature of approximately 450 degrees Fahrenheit. Thesefluxing-temperatures were found a to be lower than themelting-temperature of either component of the fiuxesl Themeltingtemperature of the ammonium pentachlorodizincate is approximately480 degrees Fahrenbelt. The melting-temperature of the zinc chloride isapproximately 540 degrees Fahrenheit, which is also approximately thedegree of heat which decomposes ammonium chloride, which substance doesnot liquefy from the effect of a sole degree of heat alone. The flux ofthe first mixture and the flux of the second mixture, both, gave thefollowing results on examination. An excess ofthe crystalline zincchloride, added to a portion of the flux, remained in the solid phase ata temperature of approximately 450 degrees Fahrenheit. An excess of thecrystalline ammonium pentachlorodizincate, added to a por tion of theflux, remained in the solid phase at a temperature of approximately 450degrees Fahrenheit. An excess of crystalline ammonium chloride, added toa portion of the flux, chemically combined with thezinc chloride to formammonium pentachlorodizincate at a temperature of approximately 450degrees Fahrenheit. This was evidenced by the amount of the ammoniumpentachlorodizincate which was separated from the flux as a result ofthe addition of the ammonium chloride. From out of the flux liquefied bythe temperature of approximately 450 degrees Fahrenheit, the ammoniumpentachlorodizincate was separated sufficiently additionally in amountto effect the return of the ratio of the amounts of the components ofthe flux to approximately equi-molecular proportions of ammoniumpentachlorodizincate and zinc chloride. By the means of chemicalanalysis the chemical composition of the substance thusseparated wasfound to conform to the chemical composition'which is represented by thechemical formula NH4ZnzCl5.

Now, in its application to the cracked hydrocarbon vapors formed frommineral oil containing asphalt, the solid phase of the ammoniumpentachlorodizincate receives a protective coating of the carbonizedpolymerized gums. Various gasoline vapors and various gum-formingimpurities become polymerized by the catalytic action of ammoniumpentachlorodizincate. Various gasoline vapors, not polymerized byammonium pentachlorodizincate at temperatures which are lower than themelting-temperature of ammonium pentachlorodizincate, become polymerizedby the ammonium pentachlorodizincate at temperatures which are higherthan the melting-temperature of the ammonium pentachlorodizincate. At atemperature of approximately 450 to 480 degrees Fahrenheit, it was foundthat ammonium pentachlorodizincate was in the solid phase, that variousgasoline vapors were not polymerized by'the ammoniumpentachlorodizincate and that the gum-forming impurities werepolymerized by the ammonium pentachlorodizincate. At higher temperaturesthan 480 degrees Fahrenheit theliquid phase of the ammoniumpentachlorodizincate could not become enveloped with the protectivecoating of the carbonized polymerized gums, but an appreciable degree ofchemical decompositionof ammonium' pentachlorodizincate ensued from theefiecting of the liquefaction of the ammonium pentachlorodizincate bythe degree-of heat solely-suflicient toefiect the liquefaction of theammonium pentachlorodizincate by the means-of itself alone; a

Now then, instead of incurring this envelopment of the ammoniumpentachlorodizincate With'aprotective coatingof the carbonizedpolymerizedg-ums, I employ the use of the sufficiency of the "ammoniumpentachlorodizincate necessary to prevent the'separation ofthe solidphase of the zinc chloride and also of the sufficiency of thezincchloride-necessary to prevent" the separation of' the solid phase of theammonium pentachlorodizincate at the temperaturebelow themelting-temperature of ammonium pentachlorodizincateand at thetemperature above the fusion-temperatureofthe fused mixture of theammonium pentachlorodizincate and of the zinc chloride.

When petroleum oil'containing compounds of sulphur'is 'sufiicientlyheated, hydrocarbon vapors containing hydrogen sulphide are formed.-When the hydrocarbon vapors containing the hydrogen sulphide arecontacted with the fused mixture of ammonium pentachlorodizincate andzinc chloride, 7 thehydrogen sulphide decomposes the zinc chloride toform'hydrogen chloride and zinc sulphide. It was found that asuificiency of the hydrogen chloride reversed the equilibrium of thereaction and prevented separation of zinc sulphide. It was effected'bythe sufficiency of the hydrogen chloride necessary in the vapor phase'tomaintain the equilibrium between the concentration-of hydrogenchloride'in the hydrocarbon vapors and the concentration of hydrogenchloride in the fused mixture; e r

' Now then, instead of incurring the formation of zinc sulphide in thecontacting of hydrocarbon vapors containing hydrogen sulphide andhydrogen chloride'with a fused mixture'containing hydrogen chloride,"ammonium pentachlorodizincate and zinc chloride, I supply to thehydrocarbon vapors suflicient hydrogen chloride to prevent separation ofzinc sulphide'and contact the hydrocarbon vapors with "a fused mixture.containing sufiicient hydrogen chloride to prevent separation of zincsulphide, containing suincient ammonium pentachlorodizincate to preventseparation of zinc chloride and containing surficient zinc chloride toprevent separation of ammonium pentachlorodizincate at a temperaturebelow the melting-temperature of ammonium pentachlorodizincate and at atemperature above the fusion-temperature of the mixture.

I will hereinbelow describe a preferred embodiment of my improvements inthe processes of contacting hydrocarbon vapors with zinc chloride. Thedescription is of an example which portrays my improvements in anillustrative manner. It is to be understood that my invention is notlimited nor restricted to the employment of the uses of the precisemixtures, concentrations, quantities, proportions, temperatures norpressures whose uses are employed in the operation of the illustrativeapplication which 'is thus *hereinbelow described as being a practicalexample of the operation of a process portraying 'my improvements.

In the application of such an illustrative process petroleum oil, whichcontains compounds or" carbon, compounds of hydrogen, compounds ofoxygen, compounds of nitrogen and compounds of sulphur, may becontinuously supplied to a. suitable cracking heater and may becontinuously cracked by the processes which are well-known to those whoare skilled in the art ofmanufacturing gasoline from petroleum oil;Thereby there may be continuously formed a vapor phase containinghydro-carbon vapors, polymerizable gum-forming impurities, polymerizablecolor-forming impurities, polymerizable gasoline vapors, hydrogen,hydrogen sulphide and steam. The cracked hydrocarbon vapors may becontinuously separated and withdrawn from the residue not taking thevapor phase. The withdrawn hydrocarbon vapors may then be continuouslypartially cooled and partially condensed. The partially cooledhydrocarbon vapors may then be continuously separated and withdrawn fromthe condenser hydrocarbon liquid ata pressure of approximately topoundsper square inch gage pressure and at a temperature ofapproximately 480 to 520 degrees Fahrenheit. The withdrawnhydrocarbonyapors may then be continuously expanded to a. pressuresuitable for the effecting of the polymerization of the gum-formingimpurities.

The various pressures of the different stages of the applicationof thetreatment for the removal of gum-forming impurities may besatisfactorily controlled'by' suitable pressure regulators'whichare'well-known to those whom are skilled in theart of treatinghydrocarbon vapors. Prior to the entry of the 'hydrocarbon'vapors into aprimary bubble-tower, their pressure may be stepped down from thepressure of approximately 170 to 180 pounds 'per square inch gagepressure to apressure of approximately 10 to 15 pounds per square inchgage pressure for the making of the subjection of the hydrocarbon vaporsto the catalytic polymerization of the gum-forming impuritieswhile theystill yet will remain in the superheated condition. Thereupon thepolymerized'products resulting from the contact with the fused mixturemay be readily held in the vapor phase because the temperature of thehydroca'rbon vapors is still yet above'the temperature of thecondensation of the'polymerized ginnforming impurities at the pressurewhose use is being employ'ed'in' the making of the application of thepolymerization treatment with the'fused mixture." Thereupon there iseffected a more efiicientfcontact withithe catalyzingmolecules of thefused mixture.

The expanded hydrocarbon 'vapors may then continuously be measured bypassing them through suitable orifice meters which are well known bythose whom are skilled in the art of measuring vapors. The measuredhydrocarbon vapors may then continuously be passed through suitableacid-proof equipment leading to the primary bubble-tower. The primarybubble-tower is also constructed of the acid-proof materials which arewell-known to those whom are skilled in the art of treating hydrocarbonvapors with hydrogen chloride.

Prior to the passing of the measured hydrocarbon vapors into the bottomof the primary bubble-tower, they may first continuously be passed intothe bottom of a suitable acid-vaporizing tower and then continuously bewithdrawn from it at the top thereof. The acid-vaporizing tower may bepacked with suitable lumps of silica quartz which are well-known bythose whom are skilled in the art of treating hydrocarbon vapors withhydrogen chloride. For each 1000 liters of the measured hydrocarbonvapors at the temperature of approximately 480 to 520 degrees Fahrenheitand at the pressure of approximately 10 to 15 pounds per square inchgage pressure which may continuously be passed into the bottom of thequartz acid-vaporizing tower, approximately 200 to 300 cubic centimetersof an aqueous solution containing approximately 30 to 32 per cent byweight of the hydrogen chloride may continuously be passed into the topof the quartz acid-vaporizing tower. The measured hydrocarbon vaporspass upwardly through the interstices between the lumps of quartz tomaintain a hot acid-vaporizing tower. The measured aqueous solution ofthe hydrogen chloride trickles downwardly over the lumps of quartz toevaporate off into the rising counter-current of the measuredhydrocarbon vapors to provide the presence of the sufiiciency of theconcentration in the vapor phase of the hydrogen chloride necessary tomaintain the equilibrium with the presence of the sufficiency of theconcentration in the liquid phase of the hydrogen chloride necessary toprevent the separation of the zinc sulphide when the hydrocarbon vaporscontaining the hydrogen sulphide subsequently contact the hydrogenchloride contained liquid phase composed of the fused mixture of theammonium pentachlorodizincate and the zinc chloride. The withdrawn vaporphase containing the hydrocarbon vapors also contains an approximately 3to 5 per cent by volume of the hydrogen chloride which has been added tothe vapor phase.

The hydrocarbon vapors, containing approximately 3 to 5 per cent byvolume of hydrogen chloride at a temperature of approximately 450 to 480degrees Fahrenheit and at a pressure of approximately 10 to 15 poundsper square inch gage pressure, may then continuously be passed into thebottom of a suitable primary bubbletower and continuously be withdrawnfrom it at the top thereof. A fused mixture, containing approximately70% NI-I4Zn2Cl5 and 30% ZnClz at a temperature of approximately 450 to480 degrees Fahrenheit, may then continuously be passed into the top ofthe primary bubble-tower and continuously be withdrawn from it at thebottom thereof. Within the primary bubbletower the hydrocarbon vaporsare brought into contact with the fused mixture of ammoniumpentachlorodizincate and zinc chloride by bubbling therethrough in aseries of superimposed pans which are well-known to those whom areskilled in the art of treating hydrocarbon vapors with zinc chloride inthe liquid phase. The vapors, from off of the top of each pan below,pass into the pan above at a point beneath the surface of the liquidtherein. The fused mixture, from off of the top of each pan above,passes into the pan below at a point beneath the surface of the liquidtherein.

The treating of the acidified hydrocarbon vapors in the primarybubble-tower may be controlled by the means of manipulations of theamounts of the ingredients of the fused mixtures which are continuouslybeing passed into the top of the primary bubble-tower. If expressed inthe terms computed into the amounts of ammonium chloride and zincchloride used per barrel of the condensed gasoline stock, there maycontinuously be passed into the top of the primary bubble-towerapproximately three pounds of the ammonium chloride and approximatelytwentyone pounds of the zinc chloride for each barrel of the gasolinestock which is continuously being passed into the bottom of the primarybubble-tower. By the means of the manipulations of the amounts of theammonium chloride and of the zinc chloride which are continuously beingpassed into the top of the primary bubble-tower, the resultingcomposition of the fused mixture, which is continuously being withdrawnfrom the bottom of the primary bubble-tower, is thereby carefullymaintained at the proportion of approximately 70% NH4ZI12C15 to preventseparation of ZnClz and of approximately 30% ZnClz to prevent separationof NH4ZI12C15. It was found that such a fused mixture was made up: fromapproximately 11 to 15 per cent of the ammonium. chloride and fromapproximately 85 to 89 per cent of the zinc chloride.

The temperature of the treating of the acidified hydrocarbon vaporswithin the primary bubble-tower may also be controlled by the means ofthe manipulations of the amounts and temperatures of the hydrocarbonvapors and of the fused mixtures which are continuously being passedinto the primary bubble-tower. Thereby the temperature of the fusedmixture which is continuously being withdrawn from the bottom of theprimary bubble-tower may carefully be maintained at the temperature ofapproximately 450 to 480 degrees Fahrenheit.

Gaseous ammonia may then continuously be passed into the hydrocarbonvapors which have been withdrawn from the top of the primarybubble-tower at a point just before they pass beneath the surface of theliquid in the suitable secondary bubble-tower. The ammonia may be addedto the hydrocarbon vapors in quantities which are suflicient to renderneutralization to the amount of the hydrogen chloride present wherebythe hydrocarbon vapors become rendered slightly ammoniacally alkaline.For each volume of the hydrogen chloride present in the withdrawnacidified hydrocarbon vapors there is supplied approximately one volumeof the gaseous ammonia to render alkaline the hydrocarbon vapors; i. e.3 to 5%.

The ammoniacally alkaline hydrocarbon vapors may then continuously besupplied to the bottom of the secondary suitable bubble-tower andcontinuously be withdrawn from it at the top thereof. The aqueoussolutions of calcium chloride may then continuously be passed into thetop of the secondary bubble-tower and continuously be withdrawn from itat the bottom thereof. Within the secondary bubble-tower the hydrocarbonvapors may be brought into contact with the aqueous calcium chloridesolution by bubbling therethrough in a series. of superimposed pans suchas are well-known to those'skilled in the art of treating hydrocarbonvapors. The vapors; from ofi of the top of each pan below, pass into thepan above at a point beneath the surface of the liquid therein. Thecalcium chloride solution, from off of the top of each pan above, passesinto the pan below at a point beneath the surface of the liquid therein.The calcium chloride solution partially cools and partially condensesthe hydrocarbon vapors whereby a hydrocarbon liquid. containing thepolymerized gum-forming impurities is formed. The condensing hydrocarbonvapors generate steam from the aqueous calcium chloride solution wherebythe maintaining in the vapor phase of the non-condensed hydrocarbonvapors is facilitated. The calcium chloride solution also extractsammonium chloride from the vapors. The condensed hydrocarbon liquid alsoextracts from the non-condensed hydrocarbon vapors polymerizedcolor-forming impurities that are resultant of the zinc chloridecatalysis in the primary treatment. Both the aqueous solution of thecalcium chloride and the condensed gain-containing hydrocarbon liquidmay continuously be withdrawn from the bottom of the secondarybubble-tower.

The treating of the alkaline hydrocarbon Vapors in the secondarybubble-tower may be controlled by the means of the manipulations of theamounts of the water and the amounts of the calcium chloride that arebeing passed into the top of the secondary bubble-tower. It is aimed tosupply approximately eighty pounds of the calcium chloride in aqueoussolution for each barrel of the gasoline which is supplied for thetreatment. This is in order to adequately flush away the condensinghydrocarbon liquid. Additional amounts of the calcium chloride may besupplied to the top of the secondary bubble-tower to provide for theremoval of additional amounts of the condensing hydrocarbon liquid.Additional amounts of water may be passed into the top of the secondarybubble-tower also in such quantities as are suficient to replace suchamounts of the water as may have been vaporized in the application ofthe treatment. By the means of the manipulations of the amounts of thewater and of the amounts of the calcium chloride being passed into thetop of the secondary bubble-tower, the resulting composition of theaqueous calcium chloride solution which is being withdrawn from thebottom of the secondary bubble-tower may be carefully maintained withinthe proportions of approximately 35 to 45 per cent of water and 50 to 60per cent of calcium chloride.

The temperature of this exit flow of the calcium chloride in the aqueoussolution may also carefully be maintained at a temperature ofapproximately 275 to 325 degrees Fahrenheit by the means of themanipulations of the pressures and temperatures of the hydrocarbonvapors which are continuously being supplied for the subjection to thetreatment with a maintained mixture of water and calcium chloride.

The withdrawn hydrocarbon vapors from off of the top of the secondarybubble-tower may then continuously be cooled and condensed wherebyliquefied gasoline stock is continuously formed; The liquefied gasolinestock may then continuously be separated and be withdrawn fromthe'non-condensed vapor phase.

The dissolved hydrogen sulphide may then be removed from the'liquefiedgasoline stock by the means of the'ernployment of the use of an aqueoussolution of sodium hydroxide. A treatment with an aqueous solution ofsodium plumbite and. subsequently with sulphur may then be applied bythe various processes which are well-known to those whom are skilled inthe art of manufacturing cracked gasoline from petroleum oil contain'purities with a fused treating-mixture containin approximately 70%-NH4'Z1'12C15 to prevent separation of ZnClz and containingapproximately 30%'ZnC12"-1;O prevent separation of NH4ZnzCl5 at atemperature below 480 degrees Fahrenheit and at a temperature above thefusion-tempera ture of the treating-mixture, supplying NHiZnzCls andZ11C12 to the treating-mixture, separating and withdrawing the contactedhydrocarbon Vapors from the treating-mixture, withdrawing from thetreating-mixture a mixture of NH4Zn2Cl5 and ZnClz containing products oftreatment, partially liquefying the withdrawn hydrocarbon vapors todegum the hydrocarbon vapors; separating and withdrawing thedegummedhydrocarbon vapors from 'the'gum-containing hydrocarbon liquidand withdrawing the gum-containing hydrocarbon liquid. 7

2. A process which comprises contacting hydrocarbon vapors with a fusedtreating-mixvapors with zinc chloride-without departing from turecontaining approximately-70% NI-I4Zn2Cl5 to prevent separation of ZnClzand containing approximately 30% ZnClz to prevent separation ofNHiZhzCls at a temperature below 480 degrees Fahrenheit and at atemperature above the fusion-temperature of the treating-mixture,supplying 'NH4ZI12C15 and ZnClz to the treating-mixture, separating-andwithdrawing the contacted hydrocarbon vapors from the treating-mixtureand withdrawing from the treating-mixture a mixture of NH4ZT12C15 andZnClz containing products of treatment.

3. A process which comprises contacting hydrocarbon vapors with a fusedtreating-mixture containing approximately 70% NH4ZI12C15 to preventseparation of ZnClz and containing approximately 30% ZnClz to preventseparation of NH4Z112C15 at a temperature below 480 degrees Fahrenheitand at a temperature above the fusion-temperature of 1 thetreating-mixture.

- FRANKLIN E. KIMBALL.

